The present invention relates to the control of internal combustion engines in general, and more particularly to a method of and an arrangement for operational safety and emergency driving control of an internal combustion engine with self-ignition.
There are already known various methods and arrangements for safety and emergency driving control of internal combustion engines with self-combustion, wherein signals indicative of the instantaneous operating condition of the internal combustion engine (gas pedal position signal, operating speed of the engine signal, brake position or braking light signal, and actual regulation bar position signal) are being continuously gathered and evaluated, and the operation of the engine is controlled on the basis of such parameters. It is also known to utilize electric adjustment arrangements which are controlled by electrical signals for an electronic regulation of the operation of internal combustion engines with self-ignition (Diesel engines). In this case, a central control arrangement instead of previously customary fuel metering and regulating systems, generates the requisite adjustment or regulation signals. While it is true that mechanical fuel metering systems for use in Diesel engines are to be considered reliable as far as their resistance to breakdown or failure is concerned, they are, under certain circumstances, unable to take into consideration the multitude of various operating conditions and environmental influences which are expected to be satisfied nowadays.
The utilization of electronic components in conjunction with an electronic Diesel engine control (EDC) makes it desirable to provide for extensive safety, monitoring and emergency driving measures even when the individual structural components themselves already contain provisions for failure recognition and, as the case may be, even failure correction.
It is also already known in a safety arrangement for an internal combustion engine with self-ignition, for instance, from the published German application DE-OS No. 33 01 742, to provide or gather continuously generated signals which are related to the operation of the internal combustion engine, such as, for instance, the gas pedal position, calculated desired value of the control rod displacement, engine operating speed, brake pedal position, and the like, and to form a corrected displacement value by minimum value of the control rod selection and furnish this corrected value to the adjustment regulator or controller of the EDC arrangement. This corrected value simultaneously serves for the determination of a deviation of the control rod displacement by taking into consideration the actual value of the control rod travel which is being fed back. Then, if predetermined limits are exceeded, the known operational safety arrangement reacts either by switching off the injection pump, or by switching off the electric current supply to the end stage of the adjustment regulator or controller, or by initiating an emergency driving operation. However, under certain circumstances, problems can be encountered during the operation of this known safety arrangement, since not all of the imaginable boundary or marginal conditions are taken into consideration during the establishment of the operational safety conditions. So, for instance, while is is true that it is possible to obtain an idling signal by providing a corresponding idling operation contact at the gas pedal, the thus obtained idling signal is not valid or applicable when, for instance, the internal combustion engine is provided with a driving speed regulation. Moreover, it can be contemplated that, for whatever the reasons may be (sporty driving, warning of following motorists and the like), the driver briefly actuates or even merely taps the brake pedal while the gas pedal remains in its depressed position, that is, it is not in its idling position. Thus, it may be seen that the known arrangements possess many drawbacks and at least potential problems, so that they still leave much to be desired particularly in terms of accuracy of the regulating function performed thereby.